Multi-column scanning electron microscopy system

Abstract

A multi-column scanning electron microscopy (SEM) system includes a column assembly, where the column assembly includes a first substrate array assembly and at least a second substrate array assembly. The system also includes a source assembly, the source assembly including two or more illumination sources configured to generate two or more electron beams and two or more sets of a plurality of positioners configured to adjust a position of a particular illumination source of the two or more illumination sources in a plurality of directions. The system also includes a stage configured to secure a sample, where the column assembly directs at least a portion of the two or more electron beams onto a portion of the sample.

What is claimed: 
     
       1. A substrate array comprising:
 a composite substrate formed from a plurality of substrate layers, wherein the composite substrate includes a plurality of holes; 
 a plurality of electrical components embedded within the plurality of substrate layers; 
 one or more ground contact pads coupled to at least one of a top surface or a bottom surface of the composite substrate; 
 one or more signal contact pads coupled to at least one of the top surface or the bottom surface of the composite substrate, wherein a portion of at least one of the top surface or the bottom surface of the composite substrate is shielded with a metal contact layer to mitigate at least one of charging or cross-talk between components of the substrate array, wherein at least one of the one or more ground contact pads or the one or more signal contact pads are positioned in an unshielded portion of at least one of the top surface or the bottom surface of the composite substrate; and 
 a plurality of column electron-optical elements, wherein the plurality of column electron-optical elements are positioned over the plurality of holes in the composite substrate, wherein each of the plurality of column electron-optical elements includes a plurality of 3D electron optical elements bonded to at least one signal contact pad of the one or more signal contact pads or at least one ground contact pad of the one or more ground contact pads, wherein one or more of the plurality of 3D electron optical elements includes a barrel portion inserted in a hole of the plurality of holes in the composite substrate, wherein one or more of the plurality of 3D electron optical elements includes one or more grooves formed in a raised region on an outer area of a disc portion of the one or more of the plurality of 3D electron optical elements, wherein a raised region of a particular 3D electron optical element surrounds a hole of the particular 3D electron optical element, wherein the one or more grooves provide one or more work areas for one or more 3D electron optical element fabrication processes. 
 
     
     
       2. The array in  claim 1 , wherein the plurality of electrical components embedded within the plurality of substrate layers include at least one of one or more ground traces, one or more signal traces, one or more ground vias, or one or more signal vias. 
     
     
       3. The array in  claim 2 , wherein at least one of the one or more ground traces, the one or more ground vias, the one or more signal traces, or the one or more signal vias are embedded in the plurality of substrate layers prior to forming the composite substrate. 
     
     
       4. The array in  claim 2 , wherein the one or more ground traces are electrically coupled to the at least one ground contact pad with the one or more ground vias. 
     
     
       5. The array in  claim 2 , wherein the one or more signal traces are electrically coupled to the at least one signal contact pad with the one or more signal vias. 
     
     
       6. The array in  claim 1 , wherein the composite substrate is formed from the plurality of substrate layers via at least one of pressing together the plurality of substrate layers, sintering together the plurality of substrate layers, or joining together the plurality of substrate layers via a co-firing process. 
     
     
       7. The array in  claim 1 , wherein at least some of the plurality of substrate layers are comprised of a co-fired ceramic. 
     
     
       8. The array in  claim 1 , wherein at least some of the at least one ground contact pad or the at least one signal contact pad is within a metalized coating or a metal plate. 
     
     
       9. The array in  claim 1 , wherein the at least one ground contact pad or the at least one signal contact pad is coupled to at least one of the top surface or the bottom surface of the composite substrate via at least one of a pressing process, a sintering process, an adhesion process, a thick-film process, or a thin-film process. 
     
     
       10. The array in  claim 1 , wherein at least some of the plurality of column electron-optical elements are fully fabricated via the one or more fabrication processes prior to being bonded to a particular ground contact pad and a particular signal contact pad. 
     
     
       11. The array in  claim 1 , wherein the one or more fabrication processes include a plurality of fabrication processes, wherein at least some of the plurality of column electron-optical elements are partially fabricated via a first set of fabrication processes of the plurality of fabrication processes prior to bonding the at least some of the plurality of column electron-optical elements to a particular ground contact pad and a particular signal contact pad, wherein the at least some of the plurality of column electron-optical elements are fully fabricated via a second set of fabrication processes of the plurality of fabrication processes after bonding the at least some of the plurality of column electron-optical elements to the particular ground contact pad and the particular signal contact pad. 
     
     
       12. The array in  claim 11 , wherein the first set of fabrication processes includes:
 a boring process, wherein the boring process generates a hole based on at least one critical tolerance in the at least some of the plurality of column electron-optical elements; and 
 a cutting process, wherein the cutting process generates a plurality of slots in the at least some of the plurality of column electron-optical elements, wherein the plurality of slots include a first slot and at least a second slot, wherein the first slot and the at least a second slot pass through a portion of the hole, wherein the first slot and the at least a second slot do not extend to the edge of the column electron-optical element. 
 
     
     
       13. The array in  claim 12 , wherein the at least one critical tolerance includes at least one of a bore size or a bore shape. 
     
     
       14. The array in  claim 12 , wherein the second set of fabrication processes includes:
 a cutting process, wherein the cutting process extends the plurality of slots to the edge of the at least some of the plurality of column electron-optical elements. 
 
     
     
       15. The array in  claim 14 , wherein the number of a plurality of beam deflector poles ranges from 4 beam deflector poles to 24 beam deflector poles. 
     
     
       16. The array in  claim 1 , wherein bonding the plurality of column electron-optical element to the particular ground contact pad and the particular signal contact pad includes at least one of a soldering process, a brazing process, or an adhesion process. 
     
     
       17. The array in  claim 1 , wherein the plurality of column electron-optical elements are inspected prior to being bonded to the particular ground contact pad and the particular signal contact pad. 
     
     
       18. The array in  claim 1 , wherein the plurality of column electron-optical elements are aligned via an aligning process while being bonded to the particular ground contact pad and the particular signal contact pad, wherein the aligning process includes at least one of aligning a plurality of lithographic target features or an optical overlay alignment process. 
     
     
       19. A substrate array comprising:
 a composite substrate formed from a plurality of substrate layers, wherein the composite substrate includes a plurality of holes; 
 a plurality of electrical components embedded within the plurality of substrate layers; 
 one or more ground contact pads coupled to at least one of a top surface or a bottom surface of the composite substrate; 
 one or more signal contact pads coupled to at least one of the top surface or the bottom surface of the composite substrate, wherein a portion of at least one of the top surface or the bottom surface of the composite substrate is shielded with a metal contact layer to mitigate at least one of charging or cross-talk between components of the substrate array, wherein at least one of the one or more ground contact pads or the one or more signal contact pads are positioned in an unshielded portion of at least one of the top surface or the bottom surface of the composite substrate; and 
 a plurality of column electron-optical elements, wherein the plurality of column electron-optical elements are positioned over the plurality of holes in the composite substrate, wherein each of the plurality of column electron-optical elements includes a plurality of 3D electron optical elements bonded to at least one signal contact pad of the one or more signal contact pads or at least one ground contact pad of the one or more ground contact pads, wherein one or more of the plurality of 3D electron optical elements includes a barrel portion inserted in a hole of the plurality of holes in the composite substrate, wherein one or more of the plurality of 3D electron optical elements includes one or more grooves formed in a raised region on an outer area of a disc portion of the one or more of the plurality of 3D electron optical elements, wherein the raised region offsets an inner area of the disc portion from the at least one signal contact pad of the one or more signal contact pads or the at least one ground contact pad of the one or more ground contact pads at a distance dependent on a height of the raised region.